1. Field of the Disclosure
The present disclosure relates to a fault current limiter. More specifically, the present disclosure relates to a fault current limiter used in a system such as electric power equipment.
2. Description of Related Art
Generally, a fault current limiter is a device protecting equipment in an electric power system by converting fault current (which occurs in accidents such as thunderstroke, grounding, and short-circuit) into normal current. Recently, various types of fault current limiters are used in related fields. The types of fault current limiter may be categorized by elements used therein, for a non-limiting example, superconductors, power semiconductors, saturated iron cores, etc.
Usually, a fault current limiter is formed of a main path and a current limiting path. The main path senses fault current when normal current is conducted, then limits or blocks the fault current at an initial stage. Being parallelly connected to the main path, the current limiting path limits or blocks the fault current by handling the fault current and the burden voltage of the main path.
When normal current flows, all the current flows to the main path, however, the current may flow to the current limiting path due to impedance difference between the parallel-connected main path and current limiting path.
FIG. 1 is a block diagram illustrating a general fault current limiter.
As shown in FIG. 1, the general fault current limiter includes a main path M and a current limiting path L. When a normal current flows, the current Itot splits into a main path current I1 and a current-limiting path current I2 by impedance difference between the main path M and current limiting path L.
At this time, the current limiting element (100) is heated by the current limiting path current I2. The larger current Itot flows, a more current will flow to the current limiting path L.
Thus, because the current-limiting path current I2 flowing in the current limiting path L acts as a loss and may impose restrictions on current limiting operations, a switch is often installed on the current limiting path L in order to block the current flowing to the current limiting path L when normal current flows.
However, in this case when there is a problem that a separate additional control circuit is required in order to open the switch on the current limiting path L at the proper time so that the fault current may detour from the main path M to the current limiting path L when the fault current occurs.